Method of converting formates into oxalates



Feb. 13, 1923. I 1,445,163;

H. W. PAULUS.

METHOD 0F CONVERTING FORMATES INTO O-XALATES.

ORIGINAL FILED JULY 26,1920. 3 SHEETS-SHEET uvwuboz ,4 fzzwmay Feb. 13, 1923. I 1,445,163.

H. W. PAULUS.

METHOD OF CONVERTING FORMATES INTO OXALATES.

ORIGINAL FILED JUL'Y 26.1920. 3 SHEETSSHEET 2.

Feb. 13, 1923.

' H. w. PAULUS.

METHOD OF CONVERTING FORMATES INTO OXALATES.

3 SHEE'TS SHEET 3 ORIGINAL FILED JULY 26.1920.

Patented Feb. 13, 1923.

umTEusTATEs PATENT oF'FicE.

.HERMAN W. PAULUS, OF RICHMOND HILL, NEW YORK, ASSIGNOR T0 ROYAL BAKING POWDER COMPANY, CORPORATION OF NEW JERSEY.

METHOD or convnn'rme FORMATES mo OXALATES.

Original application filed July 26, :1920, Serial No. 399,085. Divided and this application filed September T 0 all whom it may concern Be it known that I, HERMAN W- PAULUS, a citizen of the United States, and a resident of Richmond Hill, in the county of Queens and State of New York, have invented certain new and useful Improvements in Methods of Converting Forinates into- Oxalates, of which the following is a speci,--

fication.

The present invention relates to amethod of converting formates into 'oxalates, and more particularly, to a method of converting alkaline form ates into alkaline oxalates.

This application is a division of my copend-v ing application Serial-No. 399,085, filed" July 26, 1920; 7

' It has long been recognized that itis difficult economically to produce oxalates from for-mates on a commercial scale. The experiments seeking to increase the quantity of production and decrease the cost of production ha've'covered a long, series of years and involved the expenditure of much effort and capital. Heretofore these experiments have been more or less unsuccessful with the result that the cost of canal-ates is still relatively high. The object of the present invention is to produce a method of converting fol-mates into oxal ates by which the oxalates may be-produced quantitatively and at a relatively low cost. Theconditions under which formates may be converted into oxalates are well recognized. When the formate is subjected to atemperature ranging from 360 0. to {140 0., a-molecule of hydrogen is driven off in accordance with the following formula (sodium formate is taken to illustrate the reaction) Up to 220 0. the formate is stable. Subjected to a temperature ranging between 220- 0. and 860 0., the formate is converted into a carbonate. If the formate is subjected to a temperatureexceeding 440 0., the formate will pass through the oxalate state and be converted into carbonate-exclusively.

' mate.

This has been found- 19, 1921. Serial No. 501,735.

and maintain the receptacle at that temperature. This method has been found commercially unsatisfactory because of the low percentage of formate resulting therefrom. Other methods ofconverting for- .mates into oxalates have contemplated the addition of another compound to the for- This has required separating the forelgn element from the oxalate, which is often difiicult. and atbest an unsatisfactory and expense-involving procedure. More- 'over it has long been recognized that the temperature of the formate should be raised suddenly from about 220 0. to 360 0. or over but not exceeding 440 0.; and many eiforts have been made to satisfy this condition; but so faras known, the oxalates produced are insufli'cient in] quantity and contain too'large a percentage of carbonate.

According to the present invention the formate is converted directly into the oxalate without the addition of any foreign compound. in the presence of air. and by simply and efficiently arranging and controlling the heat zones to which the formate is subjected in orderto convert it into the oxalate. The method of the present invention consists in passing the formate through a preliminary heating zone by, which it is rendered plastic and then subjecting it to heat not greater than 220 0. by which the formate is rendered molten. perature the formate is stable and there is no liability it will be converted into carbonate. Having slowly raised the temperature of theflformate to 220 0. the liquid formate is then suddenly raised to the temperature necessaryto drive off the. molecule of hydrogen, namely, to a temperature between 360 0. and 440- 0. This is done by spreading the liquid formate thinly over hot surfaces of the requisite temperature.

' By this means the liquid formate is instantly At this temtake more than two or three seconds. It will i conversion into carbonate will be prevented.

According to the present invention themethod employed to raise the formate from its stable point to the point at which it converts into the oxalate is such that although the oxalate is produced quantitatively the formation of carbonate is almost entirely prevented.

The method ofthe invention may be prime 1 ticed in various forms of apparatus. preferred fo fm of apparatus is illustrated in the accompanying drawings, in which Fig. l is a front elevation of' the apparatus for converting formates into oxalates; Fig. 2

is a side elevation, partly in section, looking from the right in Fig. 1'; and Fig. 3 is a vertical transverse section substantially through the. middle of the apparatus shown in Fig. 1.

In practicing the method of the invention, the formate is passed in a relatively wide and thin stream through a heated zone by which the temperature of the formate is gradually raised. Passing the formate through this preliminary heating zone renders the formate more or less plastic.

The plastic formate is then introduced into a heated receptacle, the temperature of which is sufiicient to make. the plastic formate liquid. Care is exercised that the temperature of theJliquid formate does not exceed 220 (1, while it remains in the receptacle, or intermediate heating zone, as it may be termed. By preventing the formate from rising to a greater degree of temperature than 220 C. at this stage of the practice of the method, the formate is insured against being converted into a carbonate. The liquid formate is now spread 11 on a relatively large heated surface by which its temperature is suddenly raised at 360 (1, or slightly over, care being exercised that the temperature of the formats does not exceed, 440 C. lVhen the formate has been convertedinto oxalate on the heated surface, it is. scraped off as a fine white powder.

When the steps of the method briefly described above are practiced in the apparathe oxalate, means for removing the oxalate frolnfthe heated surface, and means for conveying the powdered oxalate from the apparatus. The formate in powdered or lump formats in the hopper. The formate passes out of thehopp'er into the preliminary heatin'g zone through a slot or opening 13 formed etween the forward end of the plate 11 and the flanged part 14 of the hopper. This slot extends throughout the length of the hopper. It will be recognized from the form and size of the slot 13 that the powdered formate passes down through the preliminary heating zone in a wide relativelythin stream.

In order to discharge the formate from the hopper, the plate '11 isreciprocated back and forth under the opening 12. In practice it has been found that a reciprocation movement may be increased or decreased.

The plate 11 is supported for its reciprocatory or oscillatory movements .by four arms 15, depending downwardl from hubs 16 secured to a shaft 17 journal ed in standards 18 risin from the frame 6. The plate 11 is secured in adjusted position at the lower ends of the arms 15 by check nuts 19. Oscillatory movements are imparted to the shaft 17 'by an arm 21' fastened at its upper end .to the shaft and having in its lower end a slot 22 which receives a crank or eccentric pin '23 screwed into an eccentric 24 journalledin a standard 25 supported from the table 7. The eccentric pin 23 may be adjusted in the eccentric 21 so as'to vary the length of oscillation of. the shaft 17 and so the length'of reciprocation or oscillation of the plate 11. The eccentric 24C- 7 is driven by a sprocket wheel 26 over Which passes a ch'ain427 which is driven by a second sprocket Wheel 28 mounted on one end hollow shaft 29 carries a gear 30 which meshes with a gear 31 carried by a second hollow shaft 32. The other end of the shaft 32 carries a worm gear 33 which is driven by a worm 34 mounted on a shaft 35. The

I of a hollow shaft'29. The other end of the V hollow' shafts 29 and 32 are mounted inbrackets supported from the table 7. The shaft 35 is journalled in brackets mounted on a shclf 36 supported from the table 7.

, Ward with the plate is prevented from mov-.

The shaft carries on its outer end a beltdriven pulley 36 which is coimected with a source of power not shown.

The mode of operation of the feeding device 10 will be clearly understood when it is borne in mind that the powdered formate is relatively heavy and-has a'tendency to move withtheplate 11, unless something is in its path of travel to block it. The plate 11 is shown in substantially the neutral position. If .it is assumed that the hopper contains the'powdered formate and that the plate 11 is moved forward, that is, toward the left, viewing Fig. 3, it will be understood that the formate resting on the plate is carried forward with it and that an open space will be formed adjacent to'the bot-' tom of the rear side 39 of the hopper. Into this open 'space more formatewill fall so that as the plate 11 swings rearwardly again, the formate which had been carried foring rearwardly with the plate and the formate at the discharge end 40 of the plate 11 will fall down into the chute 20. By reason of the relatively rapid movements of the feed plate 1 1 it will be recognized that a substantially steady stream of formate drops down into the heating zones.

As the formate passes through the preliminary heating zone 9 in the chute 20 it becomes plastici The plastic formate dropsinto a heated trough 42 in which it is immediately liquefied. The trough 42 is provided with a steam jacket 43, which. is supplied with steam in any'convenient manner. Sufficient heat rises from the trough 42, and also from other sources of heat presently to be described, to keep the preliminary heating zone 9 at the requisite temperature. In fact. the whole apparatus becomes hot after a short period. of use and for this reason all the parts are made heavy inorder to prevent warping. Only a small quantity of the plastic formate falls .intothe trough momentarily'and it is immediately converted into the liquid state. The heat of the trough is so regulated that the temperature of the liquefied formate does not rise above220 C.

The liquid formate is at once taken from the trough 42 and spread upon the heated surface by whichv it is converted into the oxalate. This heated surface consists. of a. hollow cylinder or drum 45 mounted on the hollow shaft 32. The means for depositing the liquid formate on the heated surface of the drum 45 consists of a rapidly rotating splasher 46 which may be composed of sheet iron or steel mounted on a shaft 47 journalled in brackets supported from the table 7 The shaft 47 is provided with a pulley 48 over which passes a belt 49 driven by a pulley 50 on the end of the shaft 51 of a motor-52. The splasher 46 acts as a scoop to gather up the liquid formate in the bottom of the trough 42 and throw it by centrifugal force upon the revolving surface of the hot drum 45. At each revolution of the shaft 47 the splasher 46 cleans out the trough 42 sothat no formate may remain therein to be slowly converted into carbonate.

Only a thin layerof the liquid formate is spread over the heated surface of the drum 45' by the action of the splasher 46. The drum 45 is maintained at such heat that the formate upon it is almost or substantially instantaneously converted into oxalate, not

more than two or at most three seconds being required to effect the conversion. In case the liquid formate should be spread upon the drum 45 too thickly to be instantly converted'into oxalate, a second drum 54 is provided, the surface of which travels in close proximity to the surface of the drum 45, as

clearly shown in Fig. 3. If the formate on the surface of the drum 45 is so thick that it touches the surface of the drum 54 as it passes through the opening 55-between the two drums, the top surface of the material on the drum '45 will adhere to the hot surpowdered coal or otherwise. In, order that the heat may be distributed uniformly over the surfaces of the drums 45 and 54, a layer of some granular, refractoryimaterial 57 such as flint or quartz sand is provided at the. bottom of each drum. This granular material, of course, tends to remain in the bottoms of the drums as they revolve, thereby conveying the heat to the cylindrical surfaces of the drums uniformly, an action which cannot be successfully accomplished by direct heating. Radiation pyrometers may be used for registering and thermostats for controlling the outside temperature of the drums. The products of combustion may be conveyed from the apparatus through the pipe 58. The draught of the burner in the drum 54 is controlled by the damper 60, and the draught of the burner in the drum 45 is controlled by the damper 59.

The drums turn in the directions indicated by the arrows in Fig. 3. The oxalate is removed from the drum 45 by a knife-like scraper 62 supported on the upper ends of plungers 64 pivotally connected at 65 to .levers 66 pivoted to the frame of'the apparatus at 67 The'free ends, of the levers 66 rest on springs 68 surrounding the upper ends of upright rods '69. The springs 68 serve to press the scraper 62 against the surface of the drum 45 in order to keep it clean. The pressure of the springs 68 may be regulated by turning the screws 70. The oxalate is removed from the surface of the upper drum 54 by a knife-like scraper 72 secured in the lower end of plun'gers73 working in a beam 7- arranged transversely at the top of the apparatus. Pressure is exerted .upon the'scraper 72by springs 75 surrounding rods 76 the upper ends of which are received in brackets 77. The pressure of the springs 75 may be regulated by turnin; the rods 76 which are provided with squared ends. 7 8 for that purpose. The scrapers are composed of some high speed tool steel and are arranged so that the edges are kept in good scraping condition.

The oxalate removed from the surfaces of the drums and which is now in powdered form falls into a trough 80 in the lower end of which there is a screw conveyer 81 fixed on a shaft 82 journalled inthe frame of the apparatus. One end of the shaft 82 is provided with a screw gear 83 which meshes with a screw 84 mounted on one end of the shaft 35. The screw conveyor 81 conveys the powdered oxalate into a receptacle 85 provided with a removable part 86. The guard 87 is provided to prevent the oxalate scraped from the upper drum 54 from fall ing onto the floor.

It will be recognized from the description of the apparatus illustrated in the drawings that this. apparatus constitutes an effective means for carrying out the method-of the invention. Only small uantities of the formate are subjected to t e various heated zones at one time andthe heat of these zones is so regulated that there is no opportunity for the formate to convert into carbonate. Inasmuch, however, as the operation is one of great rapidity, there is a continuous. stream of formate passing into the apparatus and a continuous stream of oxalate passing out f the apparatus.

Having thus described the invention, what is claimed is 1. The method of converting formate into oxalate which comprises passing the formate through a preliminary heating zone by which the formate is rendered plastic, introducing the plastic formate into a heated receptacle by'which the formate is liquefied, preventing the formate from rising above I mamas 220 C. while in the receptacle, removing the liquid formate from the receptacle, spreading it in a thin layer over a relatively large surface having a temperature between 360 C. and 440 C. by which it is con verted into oxalate, and removing the oxalate from the heated surface.

2. The method of converting formate into oxalate which comprises slowly liquefying the formate and raising its temperature to' oxalate which comprises l-iquefying the formate at a temperature not higher than 220 C. and then suddenly raising the temperature of theformate to a point between 360 C. and 440 C. whereby the formate is converted into oxalate.

; 4. The method of converting formate into oxalate which comprises feeding the fo mate through a heated zone to render it plastic,

raising the temperature of the formate to a point not higher than 220C. to liquefy it,

spreading the liquid formate out in thin layers and suddenly raising its temperature to a point between 360 C. and'440" C. whereby it is converted into oxalate.

5. The method of converting formate into oxalate which comprises subjecting the formate to heat to render it plastic, raising the temperature of the plastic formate not higher than 220 C. to liquefy it, and then suddenly raising the temperature of the liquid formate to a point between 360 C. and 440 0. whereby it is. converted. into oxalate. Q

' 6. The method of converting formate into oxalate which comprises bringing formate in contact with a surface maintained at a temperature not greater than 220 C. whereby the formate is liquefied, and then bringing the liquefied formate in contact with a surface maintained at a temthe perature between 360 C. and 440 C. where.-

HERMAN w. PAULUS." 

